The invention relates generally to a vertical break disconnect switch for high voltage applications and, more particularly, to a horizontally or underhung mounted vertical break disconnect switch including apparatus for detecting that the switch blade has closed properly into its corresponding parting contacts, i.e., the break jaws.
In electric power systems, high voltage disconnecting switches are employed to isolate transmission lines and high voltage electrical apparatus to permit the inspection or repair of such apparatus or redirect power or other reasons. High voltage vertical break disconnect switches are a type of high voltage disconnecting switch that typically have relatively long and some what flexible switch blades that are prone to suffer from wear, from improper installation, from weathering or from improper or incomplete operation, thereby causing the switch blades to not fully seat in their parting contacts, i.e., break jaws, for proper full-rated current carrying capability. From ground level, a utility operator may not be able to see whether proper closure of the vertical break disconnect switch has occurred with full seating of a switch blade contact portion within the oppositely disposed break jaw contacts and remote closure by a motor operator offers no ability to review the correctness of the closure before energization.
High voltage vertical break disconnect switches, including horizontally mounted high voltage vertical break switches are characterized by the elongated switch blade when closing to first swing about a stationary pivot at the proximal end of the blade in a first switch closing operation and subsequently rotate about its own axis in a second switch closing operation. A reverse operation of the switch takes place during opening. As such a horizontally mounted vertical break disconnect switch blade when closing in the first switch closing operation first swings about a stationary pivot from a vertical orientation to a horizontal orientation where an elongated blade contact portion or tip carried at the distal end of the switch blade comes into first contact with a break jaw stop of the break jaw assembly at an intermediate closing position of the switch. The switch blade then, in the second switch closing operation, rotates about its own longitudinal axis between the parting contact jaws, with the blade tip's side edges forcing the parting contact jaws to spread until desirably full contact with the oppositely disposed break jaws is accomplished in the final closing of the switch. The side edges of the blade contact portion or tip at full contact are typically about horizontal when in full contact with the contact fingers of the break jaws. A basic patent for such a high voltage vertical break switch is disclosed in U.S. Pat. No. 2,521,484, by Frederick G. Schmidt, issued Sep. 5, 1950. U.S. Pat. No. 4,379,956 by Charles M. Cleaveland, et al. issued Apr. 12, 1983, discloses an improved switch-jaw construction for a disconnecting switch have a tie-rod assembly interconnecting the free ends of the confronting switch jaw of the type that may be used in such high voltage vertical break switches. The said U.S. Pat. No. 4,379,956 is incorporated herein by reference as though fully set forth.
U.S. Pat. No. 5,874,900 by Andrew S. Panto issued Feb. 23, 1999, discloses a fairly complex monitoring system for an overhead power line switch which includes electronic sensors for monitoring critical switch adjustment dimensions, switch position, switch status and other switch parameters. In one embodiment the electronic sensors are positioned to sense at least one of whether the contact blade is toggled closed position or a switch-open position, whether the contact blade is aligned with the clip assembly, the contact blade depth in the clip assembly. The monitoring system is preferably provided with a remote terminal unit delivering sensor data to a remote operating facility.
It is therefore an object of the present invention to provide a horizontally mounted high voltage vertical break disconnect switch with a simple reliable apparatus for providing a positive indication when the blade tip of such a switch has come into full contact with the oppositely disposed break jaws.